I have an app that has 4 buttons on one view that display a single modal view when pressed. I would like each button to display a different picture in an image view on the modal view. How do I pass the info from the view to the modal view? Does xcode support global variables? I need this one variable to accomplish what I want to do.
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iOS Are there global variables in xcode?
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XCode is an IDE. It's not a programming language.
Objective-C is a programming language. And is the one you are using. Whilst it does support global variables I would argue they are almost never the correct solution. In this case they are 100% not the correct solution. You should be able to pass state between your controllers without using global variables. It would seem clear that when your button is pressed you know what the image is and are creating/displaying your modal view right there. Just pass it the image!
Objective-C is a programming language. And is the one you are using. Whilst it does support global variables I would argue they are almost never the correct solution. In this case they are 100% not the correct solution. You should be able to pass state between your controllers without using global variables. It would seem clear that when your button is pressed you know what the image is and are creating/displaying your modal view right there. Just pass it the image!
Why don't you post your code showing your attempt at doing this. I'm not about to post code for you to copy and paste: you learn nothing that way.
Xcode will compile plain C. And global variables in C are very easy. Just stick them outside any subroutine and reference them with extern.
But if you want a button to tell a view to display something, why not just have the button send the view a message? Even if the button doesn't know which view, it could post a notification for any random view to listen in on.
But if you want a button to tell a view to display something, why not just have the button send the view a message? Even if the button doesn't know which view, it could post a notification for any random view to listen in on.
Ok, here's what I have so far.
The modal view displays, but the image is not "mercury.png". I don't know if this is enough for you to know what is wrong, but let me know. Thanks.
Code:
DataViewController *mvc = [[[DataViewController alloc] initWithNibName:@"DataView" bundle:[NSBundle mainBundle]] autorelease];
dataViewController.planet.image = [UIImage imageNamed:@"mercury.png"];
dataViewController.view.backgroundColor = [UIColor blueColor];
[self presentModalViewController:mvc animated:YES];The modal view displays, but the image is not "mercury.png". I don't know if this is enough for you to know what is wrong, but let me know. Thanks.
It's generally a bad idea to grope other view controllers views. What your code should do when building the view controller to be presented is to have an ivar/property in the second view controller for the image. Set that value, not the imageView like you're doing now. Then in the viewDidLoad method of the second view controller set the image to the imageView. Same for the background color.
A view controller's nib isn't loaded until it's pushed. So the planet imageView doesn't exist at the point that your code is groping it.
A view controller's nib isn't loaded until it's pushed. So the planet imageView doesn't exist at the point that your code is groping it.